Novel iodinated tracers, MIBG and BMIPP, for nuclear cardiology

With the rapid growth of molecular biology, in vivo imaging of such molecular process (i.e., molecular imaging) has been well developed. The molecular imaging has been focused on justifying advanced treatments and for assessing the treatment effects. Most of molecular imaging has been developed using PET camera and suitable PET radiopharmaceuticals. However, this technique cannot be widely available and we need alternative approach. 123I-labeled compounds have been also suitable for molecular imaging using single-photon computed tomography (SPECT) 123I-labeled meta-iodobenzylguanidine (MIBG) has been used for assessing severity of heart failure and prognosis. In addition, it has a potential role to predict fatal arrhythmia, particularly for those who had and are planned to receive implantable cardioverter-defibrillator treatment. 123I-beta-methyl-iodophenylpentadecanoic acid (BMIPP) plays an important role for identifying ischemia at rest, based on the unique capability to represent persistent metabolic alteration after recovery of ischemia, so called ischemic memory. Since BMIPP abnormalities may represent severe ischemia or jeopardized myocardium, it may permit risk analysis in CAD patients, particularly for those with chronic kidney disease and/or hemodialysis patients. This review will discuss about recent development of these important iodinated compounds

Oligotrophy and pelagic marine bacteria:Facts and fiction

Oligotrophy, or the inability of bacterial cells to propagate at elevated nutrient concentrations, is a controversial phenomenon in microbiology. The exact cause of the unculturability of many indigenous marine bacteria on standard laboratory media has still not been resolved. Unfortunately the physiology of such cells is difficult to investigate as long as high cell density cultures cannot be obtained. An extensive evaluation of experiments relating to oligotrophy and the cultivation of marine bacteria is presented in this review. When incorporating the findings of studies performed with molecular biological methods, the picture emerges that indigenous marine bacteria can be cultivated under certain conditions and that the 'oligotrophic way of life' is a transient characteristic. Although strong generalisations should not be made with respect to a biological system as diverse as the world's oceans, it should be anticipated that cells with unique physiological characteristics appear to exist in the oceanic system. When combining conventional physiological approaches with molecular biological techniques it is feasible to unveil the phenotypes that go with the encountered genotypes. In view of the enormous complexity of the oceanic system this will prove an ambitious, yet resourceful undertaking

Random copolymer adsorption: Morita approximation compared to exact numerical simulations

We study the adsorption of ideal random lattice copolymers with correlations in the sequences on homogeneous substrates with two different methods: An analytical solution of the problem based on the constrained annealed approximation introduced by Morita in 1964 and the generating functional (GF) technique, and direct numerical simulations of lattice chains averaged over many realizations of random sequences. Both methods allow to calculate the free energy and different conformational characteristics of the adsorbed chain. The comparison of the results for random copolymers with different degree of correlations and different types of nonadsorbing monomers (neutral or repelling from the surface) shows not only qualitative but a very good quantitative agreement, especially in the cases of Bernoullian and quasi-alternating random sequences.Comment: 19 pages, 9 figure

Adsorption of symmetric random copolymer onto symmetric random surface: the annealed case

Adsorption of a symmetric (AB) random copolymer (RC) onto a symmetric (ab) random heterogeneous surface (RS) is studied in the annealed approximation by using a two-dimensional partially directed walk model of the polymer. We show that in the symmetric case, the expected a posteriori compositions of the RC and the RS have correct values (corresponding to their a priori probabilities) and do not change with the temperature, whereas second moments of monomers and sites distributions in the RC and RS change. This indicates that monomers and sites do not interconvert but only rearrange in order to provide better matching between them and, as a result, a stronger adsorption of the RC on the RS. However, any violation of the system symmetry shifts equilibrium towards the major component and/or more favorable contacts and leads to interconversion of monomers and sites.Comment: 15 pages, 7 figure

Precise estimation of shell model energy by second order extrapolation method

A second order extrapolation method is presented for shell model calculations, where shell model energies of truncated spaces are well described as a function of energy variance by quadratic curves and exact shell model energies can be obtained by the extrapolation. This new extrapolation can give more precise energy than those of first order extrapolation method. It is also clarified that first order extrapolation gives a lower limit of shell model energy. In addition to the energy, we derive the second order extrapolation formula for expectation values of other observables.Comment: PRC in pres

An extrapolation method for shell model calculations

We propose a new shell model method, combining the Lanczos digonalization and extrapolation method. This method can give accurate shell model energy from a series of shell model calculations with various truncation spaces, in a well-controlled manner. Its feasibility is demonstrated by taking the fp shell calculations.Comment: 4 pages, 5 figure

Reduced 123I-BMIPP uptake implies decreased myocardial flow reserve in patients with chronic stable angina

Purpose Long-chain fatty acid (LCFA) is the main energy source for normal myocardium at rest, but in ischemic myocardium, the main energy substrate shifts from LCFA to glucose. 123I-BMIPP is a radiolabeled LCFA analog. In chronic stable angina without previous infarction, we suppose that reduced 123I-BMIPP uptake is related to the substrate shift in myocardium with decreased myocardial flow reserve (MFR). The purpose of this study was to relate 123I-BMIPP uptake to rest myocardial blood flow (MBF), hyperemic MBF, and MFR assessed with 15O-water positron emission tomography (PET). Methods We enrolled 21 patients with chronic stable angina without previous infarction, all of whom underwent 123I-BMIPP single-photon emission computed tomography (SPECT) and 15O-water PET. The left ventricle was divided into 13 segments. In each segment, rest MBF and hyperemic MBF were measured by PET. 123I-BMIPP uptake was evaluated as follows: score 0=normal, 1=slightly decreased uptake, 2=moderately decreased uptake, 3=severely decreased uptake, and 4=complete defect. 123I-BMIPP uptake was compared with rest MBF, hyperemic MBF, and MFR. Results The numbers of segments with 123I-BMIPP scores 0, 1, 2, 3, and 4 were 178, 40, 25, 24, and 0, respectively. The rest MBFs for scores 0, 1, 2, and 3 were 0.93±0.25, 0.86±0.21, 0.97±0.30, and 0.99±0.37 ml/min/g, respectively. The hyperemic MBFs for scores 0, 1, 2, and 3 were 2.76±1.29, 1.84±0.74, 1.37±0.39, and 1.08±0.40 ml/min/g, respectively. The MFRs for scores 0, 1, 2, and 3 were 3.01±1.38, 2.20±0.95, 1.44±0.22, and 1.10±0.26, respectively. As 123I-BMIPP uptake declined, hyperemic MBF and MFR decreased. Conclusion In chronic stable angina without previous infarction, reduced 123I-BMIPP uptake implies decreased MFR